Shutter for camera

Abstract

A shutter for a camera having a small size is driven by coil patterns formed in a spiral shape on at least one of a fixed printed board and a movable printed board. On faces of a shutter base plate and a sector ring opposed to each other, a cam mechanism for making the sector ring progress and regress in an optical axis direction is provided. The cam mechanism comprises end face cams arranged in a concentric shape and cam followers corresponding thereto to facilitate pivoting of the sector ring in closing the shutter by moving the cam followers along downwardly inclined faces of the cams.

What is claimed is:  
     
       1. A shutter for a camera, comprising: 
       a supporting plate having an opening therethrough;  
       a fixed printed board fixed to the supporting plate and having a plurality of fixed coil patterns disposed substantially in a concentric shape relative to a center of an optical axis of the opening;  
       a shutter base plate confronting the supporting plate;  
       a movable printed board pivotably supported by the shutter base plate to confront the fixed printed board, the movable printed board having a plurality of coil patterns disposed thereon which, in an initial position of the movable printed board, are deviated from the respective coil patterns formed on the fixed printed board by a predetermined angle;  
       a biasing member for biasing the movable printed board so that the coil patterns disposed thereon are deviated at the initial position by the predetermined angle;  
       a drive circuit for selectively conducting electricity to the coil patterns on the fixed printed board and the movable printed board to generate an attractive or repulsive magnetic field therebetween to cause the movable printed board to undergo pivotal movement with respect to the fixed printed board;  
       a cam mechanism provided on the movable printed board and the shutter base plate to produce a pivotal force applied to the movable printed board in response to a force applied to the movable printed board in a direction of the optical axis; and  
       a sector member engaged to undergo pivotal movement with the movable printed board so as to open and close the opening in response to pivoting of the movable printed board.  
     
     
       2. A shutter for a camera according to  claim 1 ; wherein the cam mechanism comprises end face cams disposed substantially in a concentric shape relative to the center of the optical axis on a surface of one of the shutter base plate and the movable printed board, and cam followers projecting from a confronting surface of the other one of the shutter base plate and the movable printed board to engage the end face cams. 
     
     
       3. A shutter for a camera according to any one of claims  1  or  2 ; wherein each of the printed boards comprises a multilayer printed circuit board having at least two or more faces, the respective coil patterns are arranged on the faces of the respective printed boards facing each other or on at least two faces of each of the printed boards, and the respective coil patterns formed on the respective faces of the printed boards are connected to each other. 
     
     
       4. A shutter for a camera according to any one of claims  1  or  2 ; wherein the drive circuit conducts electricity to the respective coil patterns in a first direction to open the sector member when starting to drive the shutter and conducts electricity to either one of the respective coil patterns to in a reverse direction to close the sector member when closing the shutter. 
     
     
       5. A shutter for a camera, comprising: 
       a supporting plate having an opening therethrough;  
       permanent magnets concentrically arranged on the supporting plate;  
       a shutter base plate confronting the supporting plate;  
       a movable printed board pivotably supported by the shutter base plate to confront the permanent magnets, the movable printed board having a plurality of coil patterns disposed thereon which, in an initial position of the movable printed board, are deviated from the permanent magnets by a predetermined angle;  
       a biasing member for biasing the movable printed board so that the coil patterns disposed thereon are deviated at the initial position by the predetermined angle;  
       a drive circuit for selectively conducting electricity to the coil patterns on the movable printed board to generate an attractive or repulsive magnetic field therebetween to cause the movable printed board to undergo pivotal movement with respect to the fixed printed board;  
       a cam mechanism provided on the movable printed board and the shutter base plate to produce a pivotal force applied to the movable printed board in response to a force applied to the movable printed board in a direction of the optical axis; and  
       a sector member engaged to undergo pivotal movement with the movable printed board so as to open and close the opening in response to pivoting of the movable printed board.  
     
     
       6. A shutter for a camera according to  claim 1 ; wherein the fixed printed board comprises a disk-shaped printed circuit board having the coil patterns printed thereon and an opening formed in a center thereof in alignment with the opening formed in the supporting plate. 
     
     
       7. A shutter for a camera according to  claim 1 ; 
       wherein the shutter base plate has an opening formed there through in alignment with the opening formed in the supporting plate.  
     
     
       8. A shutter for a camera according to  claim 1 ; wherein the movable printed board comprises a disk-shaped printed circuit board having the coil patterns printed thereon and an opening formed in a center thereof in alignment with the opening formed in the supporting plate. 
     
     
       9. A shutter for a camera according to  claim 1 ; wherein the shutter base plate, the fixed printed board and the movable printed board have openings formed therein in alignment with the opening formed in the supporting plate. 
     
     
       10. A shutter for a camera according to  claim 1 ; wherein the biasing member comprises a spring. 
     
     
       11. A shutter for a camera according to  claim 2 ; wherein the end face cams comprise projections having surfaces inclining downward in a direction of forward pivotal movement of the sector member, so that when a repulsive magnetic force is produced between the coils of the movable printed board and the fixed printed board in the optical axis direction, the cam mechanism produces a force component in a pivotal direction of the movable printed board to cause the movable printed board to pivot against the biasing force of the biasing member. 
     
     
       12. A shutter for a camera, comprising: a shutter base plate; a movable plate pivotably supported by the shutter base plate and having magnetic field generating elements disposed thereon; one or more sector members engaged to the movable plate to undergo pivotal movement therewith for opening and closing a shutter aperture of the camera; a fixed plate confronting the movable plate and having one or more magnetic field generating elements disposed thereon confronting the magnetic field generating elements disposed on the movable plate, the magnetic field generating elements formed on at least one of the movable plate and the fixed plate comprising electromagnets for generating a magnetic field in response to a current passing therethrough; and a drive circuit for selectively supplying a current to the electromagnets to produce a repulsive or attractive magnetic field between the respective magnetic field generating elements to cause the movable plate to pivot with respect to the fixed plate to open and close the sector members. 
     
     
       13. A shutter for a camera according to  claim 12 ; wherein the movable plate comprises a disk-shaped printed circuit board having an opening in a center thereof in alignment with the shutter aperture of the camera, and having a plurality of coil patterns printed thereon in a concentric arrangement relative to the opening formed therein. 
     
     
       14. A shutter for a camera according to  claim 13 ; wherein the fixed plate comprises a disk-shaped printed circuit board having an opening in a center thereof in alignment with the shutter aperture of the camera, and having a plurality of coil patterns printed thereon in a concentric arrangement relative to the opening formed therein. 
     
     
       15. A shutter for a camera according to  claim 13 ; wherein the magnetic field generating elements disposed on the fixed plate comprise a plurality of permanent magnets. 
     
     
       16. A shutter for a camera according to  claim 13 ; further comprising a biasing member for biasing the movable plate so that the coil patterns disposed thereon are deviated by a predetermined angle from the magnetic field generating elements disposed on the fixed plate. 
     
     
       17. A shutter for a camera according to  claim 13 ; further comprising a cam mechanism provided on the movable plate and the shutter base plate to enable the movable printed circuit board to pivot in forward and rearward directions. 
     
     
       18. A shutter for a camera according to  claim 17 ; wherein the cam mechanism comprises end face cams arranged concentrically relative to the center of the opening of the shutter base plate and disposed on a surface of one of the shutter base plate and the movable plate, and cam followers projecting from the other one of the shutter base plate and the movable printed board. 
     
     
       19. A shutter for a camera according to  claim 18 ; wherein the end face cams have surfaces inclining downward in an opening direction of the sector members, so that when a repulsive force is produced between the coils of the movable board and the fixed board in the optical axis direction, the cam mechanism produces a mechanical force component in a rotational direction of the movable printed board to cause the movable printed board to pivot. 
     
     
       20. A shutter for a camera according to  claim 13 ; wherein the drive circuit supplies current to the coil patterns in a first direction to open the sector member when starting to drive the shutter and supplies current to the coil patterns in a reverse direction to close the sector members when closing the shutter.